PURPOSE
To lay down the procedure for bulk and tapped density.
APPARATUS
Tap density tester (Electro lab, model 1020 or equivalent)
Analytical balance
Measuring cylinder
Funnels
REAGENTS
None
PROCEDURE
- Pass a sufficient quantity of material, required to complete the test through a 1.00 mm (No. 18 sieve) to break up agglomerates that may have formed during storage.
- Transfer about 100 g of sieved sample, weighed with 0.1% accuracy, into a 250 ml measuring cylinder without compacting. Note down the weight in g as W(g). Carefully level the powder without compacting, if necessary, and read the volume of the unsettled sample to the nearest graduated unit in ml as V0(ml).
- Mechanically tap the cylinder by raising the cylinder and allowing it to drop under its own weight in the tapped density tester. Unless otherwise specified, use the tapped density tester that provides a fixed drop of 3±0.2 mm at a nominal rate of 250±15 drops/min.
- Tap the cylinder 500 times unless otherwise specified and read the volume to the nearest graduated unit as V1(ml).
- Repeat the tapping an additional 750 times and measure the tapped volume to the nearest graduated unit as V2(ml).
- If the difference between the two volumes (V1 (ml and V2 (ml) is less than 2%, V2 (ml) is the final tapped volume.
- Otherwise repeat in increments of 1250 taps, as needed, until the difference between the succeeding measurements is less than 2%.
CALCULATION
REFERENCES
USP
BP
EP
Notes:
- If it is not possible to use 100 g of sample, the amount of the sample and the volume of the cylinder may be modified and the conditions specified with the results.
- For 250 ml cylinder, select the sample mass having an untapped apparent volume of 150 to 250 ml. A 100 ml cylinder is used for apparent volumes between 50 and 100 ml.
Tags
GTP
